Project Summary Uterine leiomyomas (fibroids) are the most common tumors found in reproductive aged women, with an overall prevalence of up to 75% by age fifty. Patients with a clinically significant fibroid burden can have multiple debilitating symptoms, making fibroids the leading indication for hysterectomy in the United States. There is a strong racial disparity in the disease, with African-American women presenting with an earlier onset of the disease, with greater severity, and having a prevalence of 89% by the age of fifty. The etiology of the disease is largely unknown, but recent discoveries that the MED12 gene is mutated in 50-70% of fibroids and that introduction of a similar mutation in mouse uteri can lead to fibroids suggest that mutant MED12 may be a key player in the etiology of uterine fibroids. However, the actual mechanisms driving the disease, in either MED12 mutant fibroids or MED12 wildtype fibroids, are unknown. This gap in knowledge has hindered the development of effective therapies that obviate the need for women to have hysterectomies. We propose to exploit next generation sequencing to perform comprehensive analyses of the epigenetic, genomic, and transcriptional landscape of different subsets of uterine fibroids for comparison with normal myometria. We will also compare fibroids from caucasian and African-American women to try to understand the disparity in the disease between these two populations, which are not currently associated with any highly significant genetic mutations. We have assembled a team of experts for tissue processing and assays, next generation sequencing, and bioinformatic analyses and have performed preliminary studies that have led us to hypothesize that a fibroid subtype-specific precision medicine approach is needed for women with symptomatic disease. We will validate our preliminary results in a larger and more diverse cohort of women with greater depth and determine whether elevated serum levels of characteristic proteins we have determined are highly expressed in specific subsets of fibroids could be used as serum biomarkers for the disease. We will perform in vitro and in vivo experiments to understand the mechanisms and pathways disrupted by their overexpression. We will use the HumanMethylation (850k/EPIC) DNA methylation array to establish whether methylation differences among the fibroid subtypes contribute to the differential expression by RNA-seq. Chromatin immunoprecipitation sequencing (ChIP-Seq) will be done between MED12 mutant and HMGA2 overexpressing fibroids and myometrial cells to compare and contrast differential binding of these chromatin modifying proteins. We will use ATAC-seq to determine open chromatin regions in the tissues of the fibroid subtypes and correlate with RNA-seq. We will be analyzing both broad and deep data to provide a better understanding of combined RNA-seq, epigenetics, and genomic landscapes found in subsets of uterine fibroids. We expect that these studies will lead to development of patient-specific/precision medicine alternatives to hysterectomy for management of this disease.